Digger teeth

ABSTRACT

A two-part digging tooth for earth moving shovels, diggers and the like comprises both an adapter and a replaceable point attached thereto. The point is held on the adapter by a pair of retainer keys at opposite sides of the assembly, fitted in complemental, mated key-way slots formed in opposed surfaces of the adapter and point so that shearing action on the keys is exerted along the longitudinal axes of the keys. A wear sleeve may be interposed between the rear of the point and a seat on the adapter, absorbing impact loading.

United States Patent 1 Lafond 1 Nov. 27, 1973 DIGGER TEETH Gilles Y. Lafond, Joliette, Quebec, Canada [75] Inventor:

[52] US. Cl. 37/142 R, 172/713 [51] Int. Cl E021 9/28 [58] Field of Search 37/141, 142; 172/713 [56] References Cited UNITED STATES PATENTS 1,815,819 7/1931 Andersen 37/142 R 3,623,247 11/1971 Stepe 37/142 R 2,984,028 5/1961 Renner et a1. 37/142 A 2,689,419 9/1954 Daniels et 37/142 A 3,079,710 3/1963 Larsen et al. 37/142 R 1,188,480 6/1916 Pemberton 37/142 R Launder et al. 37/142 A 1,107,253 8/1914 Black 37/142 A 3,526,049 9/1970 Nichols.... 37/142 A 7/1952 Smith 37/142 A Primary ExaminerEdgar S. Burr Attorney-James B. Kinzer et a1.

[5 7 ABSTRACT A two-part digging tooth for earth moving shovels, diggers and the like comprises both an adapter and a replaceable point attached thereto. The point is held on the adapter by a pair of retainer keys at opposite sides of the assembly, fitted in complemental, mated key-way slots formed in opposed surfaces of the adapter and point so that shearing action on the keys is exerted along the longitudinal axes of the keys.

A wear sleeve may be interposed between the rear of the point and a seat on the adapter, absorbing impact loading.

3 Claims, 8 Drawing Figures Patented Nov. 27, 1973 I5 Sheets-Sheet l INVENTOR. GILLES Y. LA FOND ATTORNEYS Patan ted Nov. 27, 1973 3,774,324

3 shwat ns 2 32 f I k FIG 4 FIG. 5

GILLES Y. LA FOND ATTORNEYS Patented Nov. 27, 1973 3 Sheets-Sheet 3 FIG. 6

FIG.-8

INV'ENTOR. GILLES Y. LA FOND ATTORNEYS DIGGER TEETH This invention relates to two-part digger teeth of the kind presented at the lip of a power shovel, trencher, bucket and like earth moving equipment.

In digger teeth of the kind involved, the usual construction comprises an adapter fastened to and projecting forwardly from the lip of the bucket or shovel. In turn, a digger tooth is mounted replaceably on the free end of the adapter allowing the tooth or so-called point to be replaced when excessively worn or, in the instance of a reversible structure, the point may be removed and rotated 180 on the adapter when one side thereof is excessively worn.

Such a construction represented by a point replaceably mounted on an adapter entails resort to a removable retainer or key joining the two parts. Usually the key is'in the form of a pin forced by a hammer into aligned openings in the point and adapter. To separate the parts, the pin may be removed as by a punch.

It can be well appreciated that the impact forces exerted on the tooth assembly in field use are of a tremendous order, such that the retainer pin or key as ordinarily arranged is subjected to bending forces of sufficient magnitude to break the pin, entailing a great deal of down time for repair.

The primary object of the present ivention is to construct a digger tooth in such a way that the point is held on the adapter by two keys (pins) which in field use will be subjected to shear forces rather than bending forces.

A further object of the present invention is to assure ample bearing surfaces between the nose of the adapter and the tip or point, reducing stresses on the keys, while at the same time enabling the point or tip to be easily mounted on the adapter.

Another object of the present invention is to so construct the parts as to establish a fulcrum point between mating surfaces of the adapter nose and the tip, offering least resistance to the keys.

A further object of the present invention is to construct the adapter with a boss of reduced dimension at its forwardmost end, bearing against an internal wall of the point, the boss absorbing impact loading with the advantageous effect of reducing loads on the pin. A related object of the present invention is to allow a wear sleeve or collar to be interposed between the point and adapter in a floating relationship, the collar serving to increase the life of the adapter.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what'is now considered to be the best mode contemplated for applying these principles. Other embodiemtns of the invention embodying the same of equivalent principles may be used and structural changes may be madeas desired by those skilled inthe artwithout departing from the present invention.

In the drawings:

FIG. 1 is a perspective view of a digger tooth constructed in accordance with the preferred embodiment of the present invention;

FIG. 2 is an exploded view showing the parts of the tooth for assembly;

FIG. 3 is a fragmented sectional view of the tooth assembly substantially on the line 33 of FIG. 1;

FIG. 4 is a fragmented side elevation of the assembly substantially on the line 4-4 of FIG. 1;

FIG. 5 is a top plan fragmented view of the assembly;

FIG. 6 is an elevation of the key or retainer pin;

FIG. 7 is a plan view of the pin along the line 7-7 of FIG. 6; and

FIG. 8 is a sectional view of the assembly substantially on the line '88 of FIG. 5.

One embodiment of the digger tooth of the present invention is identified by reference character 10 in FIG. 1, comprising an adapter 11, a tooth or point 12 and interposed wear cap 13. The adapter 11, FIG. 2, includes a forwardly projecting nose 15 of reduced dimension. The rear portion of the adapter is characterized by rearwardly extending tangs or jaws 16, vertically spaced of afford a recess 18 which is so shaped as to receive the lip of a dipper bucket, or power shovel not shown. The jaws 16 are provided with aligned openings 20 and 21 allowing a wedge or other retainer to be entered therein and passed through a corresponding opening in the lip of the bucket.

The point 12 is secured to the adapter by a pair of retainer keys or pins 23. The digging end of the point, 12B, is quite blunt, being intended for large mining shovels of 10 to 15 cubic yard capacity.

While reference has been made to a bucket or shovel on which the adapter will be mounted, it will be appreciated that this is but one example of the type of earth moving equipment to which the tooth assembly of the present invention may be attached for field use. The invention may be applied as well to dredge buckets, bulldozer scrapers, trenchers and so on.

As best shown in FIG. 3, the nose of the adapter is defined in part by a pair ofopposed upper and lower walls and 31 which converge in a forward direction. These walls are dished or recessed at 30D and 31D for a purpose to be explained. The upper and lower walls of the adapter forward of the recesses 30D and 31D are straight and are of enlarged thickness to afford bearing surfaces 32 and 33. As can be seen the bearing surfaces 32 and 33 are substantially parallel to each other. The forwardmost end of the adapter nose is characterized "by a forwardly projecting boss or protuberance 34. I

As mentioned above, thepoint or cap is secured to the adapter by a pair ofpins 23, and in accordance with the present invention the opposed side walls of the adapter nose, FIG. 2, are formed with aligned, elongated, outwardly opening recesses 38, each being a fractional part of two similar keyway slots for receiving the pins 23 when the point 12 is complementally fitted to the adapter.

The replaceable point or tooth, FIG. 3, presents a pair of spaced upper and lower walls and 41, divergent rearwardly to afford an open-ended internal cavity generally complemental to the adapter nose. The internal cavity of the tooth is'of such configuration and geometry that when the parts are fitted together, as shown in FIG. 3, the boss 34 of the adapter bears against the forward internal wall 43 of the point and the external bearing surfaces 32 and 33 of the adapter engage opposed internal bearing surfaces 44 and 45 presented by the cavity of the point 12. Preferably the internal surfaces of the point opposite the dished or recessed surfaces 30D and 31D of the adapter are also recessed at 40D and 41D. Such recessing facilitates a quick fit of the parts while nonetheless allowing for the desired bearing engagement identified above. Rearward of the dished recesses, the adapter nose, at the upper and lower walls, is provided with additional bearing surfaces 46 and 47 which extend fore and aft of the keyway recesses 38. In like manner, the internal surfaces of the upper and lower walls 40 and 41 of the point present bearing surfaces 48 and 49 engaging the bearing surfaces 46 and 47 when the parts are assembled.

It will be recognized from FIG. 3 that the retainer pins 23 have vertical axes normal to the horizontal, longitudinal axis of the tooth assembly. Consistent with this, the opposed side walls as 50 'of the point, FIG. 8, are each formed, on the internal surface thereof, with an outwardly opening key-receiving recess 52. When the point 12 is on the adapter, each internal recess 52 of the point is aligned with the mating recess 38 of .the adapter. The recesses 52 are extended through the upper and lower walls 40 and 41 of the tooth and are manifest in 360 end apertures 53, each in effect being counter-sunk to facilitate insertion of the pins 23 from either the top aperture 53 or the bottom aperture 53.

The retainer pins may be of different form, but a preferred construction is shown in FIGS. 6 and 7. Each pin or key 23 includes a pair of opposed legs 55 separated by and vulcanized to a rubber or other resilient insert 56. In the free or unmounted state, the key is of greater diameter than the key slot represented by the aligned recesses 38 and 52, but the interposed resilient member 56 is permissive of compression of the pin as it is driven home.

Working forces exerted on the extended end of the point 12 will usually be in the direction of the longitudinal axis of the assembly'and consequently the retainer pins are subjected to shear forces and not bending moments as ordinarily. However, in the event the working forces do tend to turn the point about the longitudinal axis of the assembly, the engaged bearing surfaces 32-44 and 33-45 become fulcrum areas tending to take stresses off the retainer pins. Consequently it will be seen that the tooth assembly under and in accordance with the present invention presents ample hearing surfaces between the adapter nose and the point or tip allowing for fulcruming as noted, taking stress off the pins, and in the course of ordinary work performance the retainer pins will ordinarily be subjected to shear forces. The boss 34 at the forwardmost end of the adapter will take most of the direct, impact loading and at the same time will restrict wear which ordinarily would take place between the mating surfaces of the assembly. It will be recognized that the arrangement could be altered so that the pins will lie on horizontal axes rather than vertical axes, since in either arrangement the forces exerted on the pins will be shearing forces.

The parts are fully symmetrical about the longitudi nal axis of the assembly. Therefore, the point may be reversed when one side is worn excessively, and this is equally true of the wear cap, which, incidentally, is in a floating state and need not itself be locked in place.

Modifications may therefore be made as desired by those skilled in the art.

I claim:

1. In a digger tooth assembly: an adapter member with a forwardly extending nose receiving complementally a replaceable digger point member secured thereto by a pair of keys,

said adapter nose being defined by forwardly con verging upper and lower walls terminating in a forwardly projecting protuberance of reduced dimension at the forwardmost end of the adapter,

opposite walls of the adapter nose each being provided with an elongated outwardly opening recess as a fractional part of two similar key-way slots,

a first pair and a second pair of bearing surfaces formed on said adapter member with at least one of said bearing surface pairs being substantially parallel, said pairs of bearing surfaces being and separated from one another by a pair of intervening concavities,

said point member presenting spaced opposed internal surfaces defining an open-ended cavity for receiving complementally the nose of the adapter member whereby the point member may be mounted on the adapter nose, said point member having internal walls to be disposed opposite the corresponding walls of the adapter member,

opposed walls of the point member each having an outwardly opening recess formed therein fractionally to complete the two keyway slots when the point member is complementally mounted on the nose of the adapter member,

said open ended cavity of the point member terminating at an internal forward wall against which the protuberance of the adapter nose abuts so that longitudinal forces encountered by the point member are absorbed by said protuberance,

opposed internal surfaces of the point member being so dimensioned as to have a tight bearing fit at areas therof corresponding to said first pair and second pair of bearing surfaces, and said key-way recesses intersecting said second pair of bearing surfaces.

2. A digger tooth assembly as in claim 1 wherein said first bearing surface pair is substantially parallel.

3. A point according to claim 1 in which said internal surfaces of the point intermediate said bearing fit areas are formed with a concavity to facilitate movement of the point on to the adapter nose. 

1. In a digger tooth assembly: an adapter member with a forwardly extending nose receiving complementally a replaceable digger point member secured thereto by a pair of keys, said adapter nose being defined by forwardly converging upper and lower walls terminating in a forwardly projecting protuberance of reduced dimension at the forwardmost end of the adapter, opposite walls of the adapter nose each being provided with an elongated outwardly opening recess as a fractional part of two similar key-way slots, a first pair and a second pair of bearing surfaces formed on said adapter member with at least one of said bearing surface pairs being substantially parallel, saId pairs of bearing surfaces being and separated from one another by a pair of intervening concavities, said point member presenting spaced opposed internal surfaces defining an open-ended cavity for receiving complementally the nose of the adapter member whereby the point member may be mounted on the adapter nose, said point member having internal walls to be disposed opposite the corresponding walls of the adapter member, opposed walls of the point member each having an outwardly opening recess formed therein fractionally to complete the two keyway slots when the point member is complementally mounted on the nose of the adapter member, said open ended cavity of the point member terminating at an internal forward wall against which the protuberance of the adapter nose abuts so that longitudinal forces encountered by the point member are absorbed by said protuberance, opposed internal surfaces of the point member being so dimensioned as to have a tight bearing fit at areas therof corresponding to said first pair and second pair of bearing surfaces, and said key-way recesses intersecting said second pair of bearing surfaces.
 2. A digger tooth assembly as in claim 1 wherein said first bearing surface pair is substantially parallel.
 3. A point according to claim 1 in which said internal surfaces of the point intermediate said bearing fit areas are formed with a concavity to facilitate movement of the point on to the adapter nose. 